Shifting the microbiome of a coral holobiont and improving host physiology by inoculation with a potentially beneficial bacterial consortium

Ying Zhang,Junde Dong,Xiancheng Lin,Yanying Zhang,Qingsong Yang,Juan Ling,Xiaoyu Tang,Jianping Yin,Lijuan Long,Hui Huang,Meilin Wu

doi:10.1186/s12866-021-02167-5

Abstract

BackgroundThe coral microbiome plays a key role in host health by being involved in energy metabolism, nutrient cycling, and immune system formation. Inoculating coral with beneficial bacterial consortia may enhance the ability of this host to cope with complex and changing marine environments. In this study, the coral Pocillopora damicornis was inoculated with a beneficial microorganisms for corals (BMC) consortium to investigate how the coral host and its associated microbial community would respond.ResultsHigh-throughput 16S rRNA gene sequencing revealed no significant differences in bacterial community α-diversity. However, the bacterial community structure differed significantly between the BMC and placebo groups at the end of the experiment. Addition of the BMC consortium significantly increased the relative abundance of potentially beneficial bacteria, including the genera Mameliella and Endozoicomonas. Energy reserves and calcification rates of the coral host were also improved by the addition of the BMC consortium. Co-occurrence network analysis indicated that inoculation of coral with the exogenous BMC consortium improved the physiological status of the host by shifting the coral-associated microbial community structure.ConclusionsManipulating the coral-associated microbial community may enhance the physiology of coral in normal aquarium conditions (no stress applied), which may hypothetically contribute to resilience and resistance in this host.

Highlights

The coral microbiome plays a key role in host health by being involved in energy metabolism, nutrient cycling, and immune system formation
Effects on coral physiology Lipid and carbohydrate concentrations of the coral samples exposed to beneficial microorganisms for corals (BMC) did not significantly differ from those of the placebo groups throughout the experiment
Calcification rates were significantly higher in BMC-treated corals compared with the placebo groups on days 7 and 21 (Fig. 1b)

Summary

Introduction

The coral microbiome plays a key role in host health by being involved in energy metabolism, nutrient cycling, and immune system formation. Inoculating coral with beneficial bacterial consortia may enhance the ability of this host to cope with complex and changing marine environments. The coral Pocillopora damicornis was inoculated with a beneficial microorganisms for corals (BMC) consortium to investigate how the coral host and its associated microbial community would respond. One marked example is the bleaching of coral on the Great Barrier Reef. Five massive bleaching events occurring in 1998, 2002 2016, 2017 and 2020, has struck all three regions of the Great Barrier Reef. The coral bleaching event of 2016, which mainly affected the northern region of the Great Barrier Reef, was the most extensive and severe, and the proportion of reefs that experienced extreme bleaching was over four times that of the events in 1998 or 2002 [9, 10]. Coral reef bleaching will cause further deterioration, bringing significant and unimaginable consequences for humans and other organisms [14, 15]

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Conclusion